Japanese patent application Kokai publication No. 5-100034 discloses a scintillation camera wherein photomultiplier tubes are closely arranged together on a top surface of a scintillator. Sockets of the photomultiplier tubes are used for mounting the photomultiplier tubes onto the scintillator. A spiral spring is disposed around each socket, connecting each photomultiplier tube with a pressing plate facing the scintillator. A photocathode of the photomultiplier tube is pressed to the scintillator and fixed thereon by the spiral spring. In this way, a predetermined spring force is used to fix each photomultiplier tube on the scintillator.
However, a problem arose in the conventional photomultiplier tubes described above. Since the photomultiplier tube itself does not include a specific fixing means, various fixing parts such as a spring and pressing plate are required for fixing the photomultiplier tubes to predetermined locations. As a result, the mounting procedures for fixing the photomultiplier tube to a predetermined location becomes troublesome, making the fixing structure more complex. Further, when these photomultiplier tubes are incorporated in a predetermined photodetecting device, sockets for inserting stem pins of the photomultiplier tube is used to fix the photomultiplier tube into the photodetecting device.
In view of the foregoing, it is an object of the present invention to provide a photomultiplier tube with improved simplicity and flexibility of mounting.
It is another object to provide a photomultiplier tube unit capable of improving assembly operations of modularized photomultiplier tubes.
It is further object to provide a radiation detector capable of improving the efficiency of assembling a plurality of photomultiplier tubes.